BULLETIN NO. IM 116JANUARY 1968

FORM 2164341

INSTALLATION ANDMAINTENANCE DATA

MODEL CUBAIR COOLED CONDENSING UNIT

7 1/2 THRU 60 TONS

INC.. 13600 INDUSTRIAL PARK BLVD.. P.O. BOX 1551, MINNEAPOLIS, MINNESOTA 55440PHONE: 545-2892. AREA CODE: 612

INTRODUCTIONMcQUAY SEASONCON air cooled condensing units arefor outdoor installation, basically designed for use

or(s) (single, dual, or tandem), air cooled condenser

with direct expansion coils, air handling units, orwith propeller fans & motors and a completely wiredcontrol panel in a heavy aluminum cabinet. The con-

water chillers. The SEASONCON air cooled condens- trol panel includes a power terminal block, circuiting units are factory assembled on a single base, breaker protection for all motor phases, starting con-wired, evacuated, performance tested, given a holding tactors, and safety and overload controls, wired andrefrigerant charge, and shipped ready for installation. ready for operations.Each unit consists of accessible hermetic compress-

NOMENCLATURE

117CUB-027s 1

D1

Air Cooled Condensing Unit

Series Designation

Nominal Capacity (Tons)

Single Compressor

Dual Compressors

Tandem Compressor

INSTALLATION

GENERAL Commerical equipment of this type is in-tended for installation by qualified refrigeration me-

chanics only. As a condition of the warranty the check,test, and startup procedure must be performed by suchpersonnel and properly reported on the form provided.Failure to do so voids the warranty. Arrangement forservice should be made prior to installation, as it isnot included in the warranty or the catalog price. Seewarranty terms on Page 3.

INSPECTION When the equipment is received, allitems should be carefully checked against the bill oflading to be sure all crates and cartons have beenreceived. All units should be carefully inspected fordamage when received. Visible or concealed damageshould be reported immediately to the carrier and aclaim filed fordamage. The electrical nameplate shouldbe checked to be sure it agrees with the power supplyavailable.LOCATION The McQUAY line of air cooled condens-ing units are designed for outdoor application. Theevaporator and accessories connected to the unit areordinarily installed indoors.

The cabinet is made of heavy reinforced aluminumpanels to g ive a fa i r ly l ight but durable uni t .

The condensing unit should be located so that allfour sides of the unit have free area for inlet air flow.The unit should not be located closer than one fandiameter from a wall or other obstructions. The unitshave an upflow condenser air discharge, with air takenin from the underside of the unit.

The unit must be mounted level. The unit is furn-ished with suitable holes in the legs and channels foruse by the riggers. See Figure 1, Page 5.

The unit location should be such that the serviceman has free access to the compressor compartmentand to the access panel and the condenser fans andmotors. If the location of the unit is such that vibra-tion may be transmitted objectionably to the building+vibration isolators should be used.

Page 4

SERVICEABILITY The compressor compartment isaccessible from the top and two sides by simply re-moving panels. Under no condition should any accesspanel be blocked or locked in place by mounting partson them or running piping through them.

On the belt driven fan units, the condenser fan motorarea has generously sized access doors for checkingthe fan motors, belts, and drive. On direct drive unitsaccess is through the fan orifice.

The control panel is protected by a weather proofenclosure having a gasketed and hinged door.

REFRIGERANT PIPING The refrigerant piping shouldbe installed according to standard practice and shouldfollow latest ASHRAE guide recommendations. In thatthe motor-compressors are resilient mounted, it isnecessary that a vibration eliminator be installed be-tween the suction connection on the compressor andthe first section of the line proper.

There must be sufficient flexibility in the piping sothat vibration from the unit is not transmitted from theequipment to the bui Iding, and so that the brazedjoints at the unit are not stressed. Loops, hairpins,or flexible connectors in the lines will be required.All refrigeration lines must be checked and secured toprevent wear or vibration at all operating conditions.

A filter-drier must be installed in the liquid line topick up acids, dirt and moisture that may be left i nthe system. A moisture indicating sight glass, locatedin the liquid line, must also be installed. A suctionline filter is also recommended to prevent grit or dirtfrom getting to the compressor.

The unit is furnished with a liquid line shut offvalve located ot the subcooler outlet.

It is urged that dry nitrogen be run through the con-necting refrigerant lines during the brazing operationto prevent oxidation of

Piping interior. Soft soldered

joints are not acceptab e.CONTROL PANEL Al l operat ional and refr igerantsafety controls are located in the control panel. Alsonote following section on fuses and circuit breakers.

ELECTRICALELECTRICAL CONTROL CENTER

The McQuay SEASONCON air cooled condensingunit has a superior electrical control center desi

.8ned

exposed terminals or contacts. All refrigeration con-trols are covered and can be adjusted without fear of

with safety and reliability as the foremost cons1 era-tion. It is enclosed in a weathertight cabinet with

contacting line voltage. Figure 6 shows dead-front

hinged access doors and key lock for added protection.panels removed to show internal controls and wiring.It is important to have a qualified electrician service

All necessary safety and operating controls are in-cluded and are factory wired in accordance with the

this panel. Unqualified tampering with the controlscan cause serious damage to equipment and void the

National Electric Code. The control cabinet, access-ible from outside the unit, protects all controls from

warronty.

accidental damage and prevents unauthorized person-WARRANTY: Warranty is voided if wiring is not inaccordonce with specifications. A blown fuse or trip-

nel from tampering with them.A partition separates the adjustable safety controls

ped protector indicates a short, ground or overload -

from the storting controls. A dead-front panel coversbefore replacing fuse or restarting compressor, thetrouble must be found ond corrected.

the starting controls to protect the operator from any

FIGURE 6

1. THERMOSTAT-FAN CYCLING

2. OIL PRESSURE CONTROL(Manual Reset)

3. HIGH PRESSURECONTROLS

4. LOW PRESSURE CONTROLS

5. TIME DELAY RELAY-COMPRESSOR SEQUENCING

Wiringwith al9

of the systems should be done in accordanceapplicable codes and ordinances.

Three main power leads must be connected to the

.13

12

8 9 10 11

6. SWITCHES-ON/OFF

7. RELAYS

8. SWITCHES-RESET9. FUSE-CONTROL CIRCUIT

10. TIME DELAY RELAY-PART WINDING START(Optional)

11. CONTACTOR-FAN MOTORS

12. CONTACTORS-COMPRESSORS

13. CIRCUIT BREAKER-FAN MOTORS

14. CIRCUIT BREAKERS-COMPRESSORS

15. POWER TERMINAL BLOCK& POWER CONNECTION

FIELD WIRING

condensing unit. Table 8, Page 16, gives the recom-mended lead wire sizes for three conductors in araceway.

Maximum supply voltage variation is ? 10% of name-plate value. Phase voltage unbalance must not exceed2%.

The condensing unit is wired to operate on a non-recsta ll

cling pumpdown cycle and it is necessary to in-I 24 volt liquid line solenoid valves in the system.

The liquid line solenoid is to be controlled by a returnair or space thermostat for air conditioning duty, or

suitable thermostat for water chilling. For dual com-pressor units, a two-stage thermostat and two solenoidvalves should be used as shown in Diagram 1, Page 11.

Although there is no specific requirement, interlock-ing of the evaporator fan motor is recommended so thecondensing unit will not run unless the evaporator fanmotor is running. This can be accomplished by inter-locking on auxiliary contact of the evaporator fanmotor starter across terminals 25 & 26 as shown inDiaaram 3. A sail switch could be wired across thesame terminals to accompl ish the

Refer to wiring diagrams providedspecific wiring diagram for each model.

same results.with units for

Page 10

UNLOADERS Cylinder unloading capacity control isavailable on all except the CUB-007S. Unloading con-sists of opening a gas by-pass circuit from the cylin-

der head to the low pressure side of the compressorby means of a solenoid valve. Unloading results whenthe solenoid valve coil is energized. The unloading iscontrolled by an open-on-rise pressure control switchin series with the unloader solenoid coil. The pressurecontrol is adjustable in both range and differential.

The pressure control is set at the factory on a nomi-nal basis. Final adjustment must be made in the fieldbased on the individual system compressor - evapora-tor balance. For nominal settings, refer to Table 15,Page 21.FUSES AND CIRCUIT BREAKERS The circuit break-ers for the compressor and condenser fan motor con-tactors are located in the control box. In addition,there are small fuses for the compressor control cir-cuits located in the end of the compressor terminalbox.A fuse in the control box also protects the controlcircuit.

Most local electrical codes also require a fuseddisconnect switch in the unit supply circuit, locatedwithin easy reach or within sight of the unit.

CONTROL WIRING INFORMATION Temperature con-trols ore usually separate from the main condensingunit controls. These controls usually consist of aliquid line solenoidvalve opened and closed by a roomthermostat. The thermostat can be either low voltageor line voltage. On a year around system consistingof cooling and heating, a combination heating andcooling thermostat is commonly used.

CRANKCASE HEATERS The compressors are equippedwith crankcase heaters. The 15HP and smaller modelcompressors have heaters installed externally belowthe crankcase. The 20HP and larger model compres-sors have heaters inserted into the crankcase.

The function of the heater is to keep the temperaturein the crankcase high enough to retard refrigerant frommigrating to the crankcase and condensing in the oil.

When a system is to be started up initially in coldombient, the power to the heaters should be turned onfor some time (at least 8 hrs.) before the compressor

system is started. The crankcase should be up toabout 8OF before the system is started up, to minimizelubrication problems or liquid slugging of compressoron startup.

I M P E D A N C E R E L A Y O V E R L O A D P R O T E C T I O N Inorder to provide reset of unit in conditioned space orat the unit, an impedance relay is incorporated into thecontrol circuit. Basically, this type of control is cen-tered around a relay with a high impedance holdingcoil connected in series with the basic relays andcontactors, but in parallel with the safety automaticreset control or controls. The impedance relay normallyclosed contacts are located in the safety control cir-cuit. A normally open momentary contact reset buttoninstalled at the panel or remotely is connected in para-llel with the relay normally closed contacts, or relaycoil.

For typical operation, refer to Diagram 2, Pages 12and 13. Note that coil of impedance relay R4 is inseries with the group of controls Ml, M2, and R2. Thecoil is also in parallel with the high pressure controlHP1, and the normally closed relay contacts R4. Innormal operation, HP1 and R4 are closed and, there-fore, there is no voltage across relay coil R4. How-ever, when the system goes out on high head pressure,control HP1 opens; R4 coil is now in series with thegroup of controls Ml, M2 and R2. Although the relaycoil R4 is in series with the group of controls, thereis sufficient voltage across it to open the normallyclosed contact R4. When the high pressure control HP1closes again on reduct ion in head pressure, thenormally closed contact R4 is still held open by vol-tage across coil R4.

It is, therefore, necessary to push reset switch S3to jumper contact R4 and drop out the impedance relayso that the system can start. A remote momentary con-tact reset switch in parallel with S3 may be installedfor remotely restarting the unit.

Where compressors have external overload protec-tion, both the HPC and the external overload controlcircuit is reset by the impedance circuit. Where com-pressors have internal overload protection, automaticreset, only the HPC outage is reset by the impedancecircuit.

DIAGRAM 1‘my: ~~c;~~‘,~‘“‘“”

!TYPICAL FIELD WIRING

I0 DIIco**rcI CUB AND AIR HANDLERm.1-)10 >Y) “OLT

NOTES:(1) R3 Relay Coil voltage

to be same as motorstarter voltage

(2) Rl and R2 Relays arein c o n d e n s i n g u n i tcontrol center.

(3 ) Al l i tems except R1a n d R 2 Relays by

others .(4) _29 Designates

termina l s t r ip num-bers in condens ingunit control center.

Page 11

EVACUATING AND CHARGING The condensing unit,as shipped from the factory, has been checked undernormal operating conditions. The unit is shipped witha holding charge of R-22 refrigerant.

Care should be used to keep the system closed aslong as possible when making the piping connections.Every precaution must be followed to prevent dirt andmoisture from entering the system. Under no conditionis the unit piping or components of the system to beexposed to atmospheric moisture. Always cap or sealall exposed pipe ends or refrigerant tubing during in-stallotion.

Standard evacuation and charging procedures shouldbe followed after piping and pressure testing is com-pleted.

NORMAL REFRIGERANT CHARGE The condensercoil has a built-in subcooler. For optimum operation,the liquid sight glass in the liquid line between thereceiver and subcooler should be substantially free ofbubbles. A completely clear sight glass indicates anovercharged system. No adverse affect need be ex-pected unless the overcharge is sufficient to createan excessive head pressure caused by appreciableliquid flooding of a portion of the condenser coil. Theminimum charge at which the unit will operate properlyis with clear sight glass between the filter-drier andthermostatic expansion valve. Sight glass, filter-drier,liquid line solenoid, and expansion valve are neces-sary and must be furnished by others.

CHARGING SYSTEMS - WITH SEASONTROL Refrig-erant systems using the SEASONTROL head pressurecontrol require a substantially larger refrigerant chargethan a standard system designed for summer use only.

The following procedures for charging the SEASON-TROL head pressure control system are recommended:A. If the ambient is such that the system is condens-

ing at a temperature of 95F or above, charge theunit like a standard unit. That is, charge until youhave a clear sight glass with a nominal reserve.Then add a charge equal to the difference betweensummer and winter charge, as given in Tables 2 &3, Pages 6 and 7.

TABLE 9

B. \L;hT; stem is char ed when the ambient is quiteF Bor lower, a d a nominal charge that might

nor;ally’ be considered a reasonable amount forthe specific system. Then cover the inlet side ofthe condenser with cardboard or other materialuntil the head pressurerises to a pressureof about225 psig to make sure the SEASONTROL headpressure control is open and that no refrigerant isblocked up in the condenser. Then add refrigerantuntil the sight glass clears up with a nominalreserve. Then add the winter operation chargewhich should be equal to the difference betweenthe required summer charge and winter charge forthe specific unit or section. See Tables 2 & 3,Pages 6 and 7.

OIL CHARGE Because of the rather large refrigerantcharge required in an air cooled condensing unit sys-tem, it is usually necessary to put additional oil intothe system. The oil level should be watched carefullyupon initial startup and for some time thereafter.

At the present time, Suniso #3G oil is the only oilapproved by Copeland for the use in these compres-sors. The oil level should be maintained at a levelabout midpoint of the glass bullseye on the compres-sor body.

S E T T I N G L O W P R E S S U R E C O N T R O L F O R L O WAMBIENT START The proper setting of the cut-outand cut-in point of the low pressure control dependsupon the lowest ambient in which the air conditioningsystem is expected to be used. Inasmuch as both thecondenser and the receiver are located in the outsideambient, it is necessary to set the low pressure con-trol at a pressure considerably lower than the pressurecorresponding to the temperature of the lowest ambientpoint. Otherwise, the low pressure control will notcut-in to get the system started; or, in marginal tem-perature, may cut-in but short-cycle.

Table 10, Page 18, shows the nominal low pressurecontrol settings for systems using R-22 refrigerant toinsure starting at the given ambient temperatures.These are nominal settings. Final settings must bebased on actual checkout of the individual system.

REFRIGERANT LINE CAPACITIES FOR REFRIGERANT R-22(TONS OF REFRIGERATION RESULTING IN A LINE FRICTION DROP PER 100 FT. EQUIV.

PIPE LENGTH CORRESPONDING TO 2F (AT) CHANGE IN SATURATION TEMP.)

Page 17

T A B L E 10CONTROL SETTING FOR LOW

AMBIENT OPERATIONLOW PRESSURE CONTROL

MINIMUM CONTROL SETTING *OPERATINGAMBIENT (F)

CUT-IN CUT-OUT(PSIG) (PSIG)

+30 50 32+20 38 20+10 28 10

0 20 5-10 12 2-20 7 0

*The settings are all for singles, duals and #1 tandemcompressor low pressure controls. #2 tandem control mustremain ret at normal setting. See Table 15, Page 21, fornormal settings.

TABLE 11WEIGHT OF REFRIGERANT (R-22) IN

COPPER LINES*LBS. PER 100 LINEAL FEET

*Type L copper tubing.

OPERATIONPERIODIC SERVICE (At end of first week of opera-tion and once a month thereafter).A .

B.

C .D .

E.

Check compressor oil level.’ Oil should cover ap-proximately 1/2 of the oil level glass. CopelondCompressors are furnished with oil fill plug on theside of crankcase.Check liquid sight glass for proper refrigerantcharge.Check belt tension, and observe condition of belts.Check condenser coil face for obstruction. If nec-essary, flush with cold water, brush off, or usevacuum cleaner.Make general inspection of entire system for anyunusual sound or condition.

WEEK END OR SHORT PERIOD SHUTDOWNA. Turn off switch closing evoporator liquid line sole-

noid valve(s).B. Wait for system to pump down.C. Turn off shut-off switch S1. Turn off evoporator

fan motor.

START UP FOLLOWING WEEK END SHUTDOWNA. Turn on evaporator fan motor.B. Turn system switch S1 to “on” position.C. Turn to “on” switch opening liquid line solenoid

valve(s). Observe operation for several minutes,noting any unusual sounds, or unusual cycling ofcompressors.

EXTENDED SHUTDOWNA .B.

C .

D.E.

Close the liquid line shut-off valve.Wait for the compressor to pump down until itshuts off on low pressure control.Turn off the power to the compressors, condenserfan motors, cronkcose heaters, and evaporator fanmotor.Close the suction and discharge shut-off valves.

Tag all opened disconnect switches warningogainst starting up the compressor before properlyre-opening the shut-off volves.

START UP AFTER EXTENDED SHUTDOWNA.B.

C.D.

FE:G.

Page 18

Inspect all equipment.Check face of condenser coil for paper or otherobstruction that might be lodged on the surface.Open the suction and discharge service valves.Turn on the electric power to the system.Open the liquid line shut-off valve or valves.Star t the a i r handler or chi l led water pump.Check crankcase heater & crankcase warmth.

H. Start the unit by turning on system switches.J. After the unit has run for severol minutes, check

the oil level in the crankcase, and observe flowthrough the refrigerant sight glass for sufficientrefrigeront charge.

SEASONTROL head pressure control Is o factory in-stalled system, based on liquid refrigerant floodingback into the condenser coil, thereby reducing the ef-fective condenser surface available for condensing.

The SEASONTROL head pressure control system isan improved method of head pressure control incorpor-ating two modulating valves. Its operotion is indepen-dent of difference of elevation between the condenserand receiver.

The main, or liquid line, valve is normally closed,and opens on Bressure, rise in the condenser. Thisvalve IS locate in the liquid line between the conden-ser and receiver. The gas, or bypass, volve is normallyopen ond closes on pressure rise. This valve is loca-ted in the line between the hot gos header and theliquid line section between the liquid SEASONTROLhead pressure control valve and the receiver. SeeFigure 9, Page 20.

The system operates OS follows: On system startup, the bypass valve is normally open and the moin orliquid valve is closed. Hot gas moves from the com-pressor, part going into the condenser, and port goingthrough the byposs circuit through the open volve ondinto the receiver. The bypass gas goes directly intothe receiver to maintain or build up pressure in thereceiver as liquid leaves. As the compressor contin-ues to run, hot gos condenses in the condenser androises the liquid level since the main valve on theleaving side of the condenser is still closed. As theliquid level in the condenser rises, the condensingcapacity of the condenser decreases and, OS a result,the head pressure rises. The bypass gas maintains orraises the pressure in the receiver. As the pressurein the condenser rises to the control point of thevalve, the liquid valve starts moduloting towards theopen position, permitting liquid to leove the conden-ser and flow into the receiver. At the same time, thebypass valve starts modulatin towards the closedposition, limiting the hot gas low into the receiver.9The modulation of the two valves maintain the properiiquid level in the condenser to mointoin proper head

Yessure.The bypass gos also warms up the cold

rquid from the condenser to near saturation tempera-ture.

CHECKINGFANTROL head pressure control is an automat icwinter control method and will maintain a condensingpressure within reasonable limits by cycling one fanon a two fan unit, or two fans in sequence on a threefan unit in response to outsideair temperature enteringthe condensing coil.

Fan motors are internal inherent overload protected,and are started by a single contactor, with the indivi-dual fan motors cycled by use of two pole, heovy dutythermostats. See Diagram 4, Page 19.

One of the more obvious advantages of multiple foncondensers over sin le fan units is the simple and in-expensive woy in wit*rch controlled capacity reductionmay be achieved. On a two fan unit, stopping one fanreduces the condenser capacity to approximately 55%of full rating. On a three fan unit, stopping two fansreduces the condenser capacity to approximately 40%of full roting.

DIAGRAM 4

Thermostats are nominally set to maintain condens-ing temperatures between a high of 120F and a lowof about 80F. The final setting of the thermostatsvaries with system design conditions. The settingsshown on Table 13, Page 19, will ordinarily give sat-isfactory operation.

Where operation at ambients below the range shownon Table 12, Page 19, are required, Seasontrol orDampertrol may be added.

TABLE 12

FANTROL head pressure control FANTROL head pressure control (Std)

SYSTEM WI RING (Ambient Low Limit)

NOTE: On CUB 0075-0285 single phase condenser fan motors areemployed and only two wires are broken by the thermostat.

CONTROLS

UNIT WITH STANDARD “NlT WITH ADDITIONALCUB _ CAPACIYY REDUCTION CAPACITY REDUCTION

!K MINIMUM MINIMUMCAPACITY “zN;?E\?

c:Tp:pe’;ryz%F

STEP 5 TEMP. m* TEMP. (Fy

zx0135 g :t

210166 50ii% 6 %

;;3% 42

0285 66% 10 33% 35OJ9T

go; :: 28 fZ :8s: 56

3:Os 48 :d

033D2;

loo 3”:25 T

:x ztfl33% 39

PData based on:Capmtv step % 100 1 67.60 1 50.20MinimumCondensing Tamp. 1 9OF 1 BOF 1 70 F

TABLE 13 FANTROL THERMOSTAT SETTING (F)

TWO FAN UNITS THREE FAN UNITSTHERMOSTAT THERMOSTAT #1 THERMOSTAT #2

CUT-IN I CUT-OUT CUT-IN I CUT-OUT CUT-IN I CUT-OUT65 55 65 55 50 40

DAMPERTROL head pressure control The dischargeside face and bypass dampers ore controlled by a pres-sure actuated operator connected to the high pressureside of the refrigeration system. As pressure increas-es in the system, the operator opens the face damperblades and closes the two bypass blades to preventrecirculation of air around the fan. The damper opera-tor starts moving at 175 psig (from closed position)and is fully extended at 250 PSIG (fully opened posi-tion).

TABLE 14DAMPERTROL head pressure control (Opt)

(Ambient Low Limit)

CUBXK

UNIT WITH STANDARDCAPACITY REDUCTION

MINIMUM

UNIT WITH ADDITIDNALCAPACITY REDUCTION

Data based on:Capacity Step %

FIGURE 7

DAMPERTROL C head pressure control

DAMPERTROL C IN OPEN POSITION

DAMPERTROL C IN BYPASS POSITION

DAMPERTROL C head pressure control sections.Show air flow in open (normal) position and closed(winter start) position. For operation to -2OF ambient.

Page 19

SEASONTROL head pressure control VALVE CHECK-ING AND SETTING The SEASONTROL head pressurecontrol valves are factory set and checked to maintaina minimum head pressure equivalent to 90F condens-ing. The valves have a nominal 15 PSIG modulatingrange between fully open and fully closed positions.Typical settings for Refrigerant-22 use is to have thevalves modulate between 160 and 175 PSIG. This willmaintain a nominal 90F condensing.

Referring to Figure 8, Page 20, it is to be noted thaton pressure Increase on the system, the pressure willtend to compress the bellows and the valve strokewill be uThis

or toward the adjustment end of the valve.app res to both the liquid and gas valves. Ther

239 series, or liquid valves, open on pressure rise.The 237 series, or gas bypass valves, close on pres-sure rise. The valve travel is a nominal one tenth inchfor all models.

A S indicated in the diagrams, the adjustment of thenut in a clockwise direction will increase the modula-ting pressure point. A wide bladed screwdriver orsimilar instrument inserted into the nut slot may beused for making the adjustment.

The modulating pressure point and range may bechecked as follows:

A. Make up a “depth gauge” for inserting through the

B.

C.

D.

E.

adjusting nut opening and long enough to hit thebottom of the bellows section as indicated inFigure 8B, Page 20. A piece of insulated wire, 8to 12 auge, is a simple and convenient materialfrom w1.rch to make a gauge. Insert a piece of thewire into the valve as shown in the diagram. Trimoff insulation, for about one inch of the end to beinserted, and at a point just above the top of thevalve at the other end. When in use hold the gaugedown lightly against the bellows and sight alongthe top of valve.A high side gauge should be connected to a lineso it can be brought to the valve area unless asecond person is available to call out head pres-sure readings while valve observations are made.Start up the unit and note pressures at which valvebellows rise. We assume that the pressure was lowenough at start up so that the bellows is in thedown position. The test may also be done in re-verse by running the system u to a high headpressure, stopping the unit, anB making observa-tions at what pressure the valve changes position.The valves should be set so that the movement ofboth valves is through the same pressure range.Be sure system has sufficient refrigerant beforemaking any change in valve adiustment.

FIGURE 8 SEASONTROL head pressure controlTYPE 239 LIQUID VALVE

8A. SECTIONAL VIEW 8B. CONTROL SETTING

FIGURE 9

EDADJUSTING NUT l/10” TRAVEL

CONTROL SPRING

FEELER GAUGE INSE

. . ..I-~“-

- - - - - - -VALVE SEAT

t

LIQUIDOUTLET

w

SEASONTROL III head pressureFor operation to -20F ombient.

HOT GAS HEADER

LIQUID HEADER

LIQUID LINE

BY PASS LINE

LIQUID VALVE

RECEIVER

RELIEF VA

PURGE VALVE

SUBCOOLER SECTION

\GAS VALVE

RTED

M A I N T E N A N C EG E N E R A L MOTOR

A. The air cooled condenser section requires a mini- A.mum of maintenance. All that is required is tolubricate the fan shaft bearings, motor bearings,and occasionally clean the surface of the coil.During the initial break-in period, it is advisableto check the belt tension after the first 48 hours of B.operation. Usually, by this time, the belts haveacquired their permanent stretch, and further ad-‘ustments should not be necessary. It is advisable,/l owever, to recheck the belt tension at 3 monthintervals and, if necessary, make any adjustments.

B. The fan shaft bearings do not require lubricationat the time the unit is out into service. The fanshaft bearings should be greased once a year usingSTANDARD OIL COMPANY Multi-PurposeLithium Grease. DO NOT OVERLUBRICATE. The

C. The coil will require a periodic cleaning and this C.can be accomplished by a brush, vacuum cleaneror a pressurized air stream.

All motors are ball bearing, pre-lubricated and donot require the addition of grease at the time of in-stallation. Periodically, the ball bearings shouldbe cleaned and the grease renewed, to gain theultimate in service from the motor bearings.Extreme care must be exercised to prevent foreignmatter from entering the ball bearings. It is alsoImportant to avoid overgreasing Only a high gradeclean mineral grease having the following charac-teristics should be used. Consistency: a littlestiffer than that of Vaseline, maintained over theoperating temperature range; melting point prefer-ably over 150C (302 F); freedom from separationof oil and soap under operating and storage condi-tions, and freedom from abrasive matter, acid alkaliand moisture.Specific greasing instructions are to be found onthe tag attached to the motor and should be gen-era I ly fol lowed.

REPLACEMENT PARTS

Replacement service parts can be ordered throu hJ

involved. Replacement parts for the motor-compressoryour nearest McQUAY representative. Always prove ecomplete description of service port, part number if

assembly can be procured direct from your nearest

known, plus complete serial and model number of unitfranchised Copeland Refrigeration Corporation Whole-saler.

INC.* 13600 INDUSTRIAL PARK BLVD., P.O. BOX 1551. MINNEAPOLIS, MINNESOTA 55440PHONE: 545-2892 l AREA CODE: 612

@